xref: /freebsd/sys/kern/sys_process.c (revision 53b70c86d93c1e4d3c76f1282e94154e88780d7e)
1 /*-
2  * SPDX-License-Identifier: BSD-4-Clause
3  *
4  * Copyright (c) 1994, Sean Eric Fagan
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by Sean Eric Fagan.
18  * 4. The name of the author may not be used to endorse or promote products
19  *    derived from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/ktr.h>
40 #include <sys/limits.h>
41 #include <sys/lock.h>
42 #include <sys/mutex.h>
43 #include <sys/reg.h>
44 #include <sys/syscallsubr.h>
45 #include <sys/sysent.h>
46 #include <sys/sysproto.h>
47 #include <sys/priv.h>
48 #include <sys/proc.h>
49 #include <sys/vnode.h>
50 #include <sys/ptrace.h>
51 #include <sys/rwlock.h>
52 #include <sys/sx.h>
53 #include <sys/malloc.h>
54 #include <sys/signalvar.h>
55 #include <sys/caprights.h>
56 #include <sys/filedesc.h>
57 
58 #include <security/audit/audit.h>
59 
60 #include <vm/vm.h>
61 #include <vm/pmap.h>
62 #include <vm/vm_extern.h>
63 #include <vm/vm_map.h>
64 #include <vm/vm_kern.h>
65 #include <vm/vm_object.h>
66 #include <vm/vm_page.h>
67 #include <vm/vm_param.h>
68 
69 #ifdef COMPAT_FREEBSD32
70 #include <sys/procfs.h>
71 #endif
72 
73 /*
74  * Functions implemented using PROC_ACTION():
75  *
76  * proc_read_regs(proc, regs)
77  *	Get the current user-visible register set from the process
78  *	and copy it into the regs structure (<machine/reg.h>).
79  *	The process is stopped at the time read_regs is called.
80  *
81  * proc_write_regs(proc, regs)
82  *	Update the current register set from the passed in regs
83  *	structure.  Take care to avoid clobbering special CPU
84  *	registers or privileged bits in the PSL.
85  *	Depending on the architecture this may have fix-up work to do,
86  *	especially if the IAR or PCW are modified.
87  *	The process is stopped at the time write_regs is called.
88  *
89  * proc_read_fpregs, proc_write_fpregs
90  *	deal with the floating point register set, otherwise as above.
91  *
92  * proc_read_dbregs, proc_write_dbregs
93  *	deal with the processor debug register set, otherwise as above.
94  *
95  * proc_sstep(proc)
96  *	Arrange for the process to trap after executing a single instruction.
97  */
98 
99 #define	PROC_ACTION(action) do {					\
100 	int error;							\
101 									\
102 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);			\
103 	if ((td->td_proc->p_flag & P_INMEM) == 0)			\
104 		error = EIO;						\
105 	else								\
106 		error = (action);					\
107 	return (error);							\
108 } while (0)
109 
110 int
111 proc_read_regs(struct thread *td, struct reg *regs)
112 {
113 
114 	PROC_ACTION(fill_regs(td, regs));
115 }
116 
117 int
118 proc_write_regs(struct thread *td, struct reg *regs)
119 {
120 
121 	PROC_ACTION(set_regs(td, regs));
122 }
123 
124 int
125 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
126 {
127 
128 	PROC_ACTION(fill_dbregs(td, dbregs));
129 }
130 
131 int
132 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
133 {
134 
135 	PROC_ACTION(set_dbregs(td, dbregs));
136 }
137 
138 /*
139  * Ptrace doesn't support fpregs at all, and there are no security holes
140  * or translations for fpregs, so we can just copy them.
141  */
142 int
143 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
144 {
145 
146 	PROC_ACTION(fill_fpregs(td, fpregs));
147 }
148 
149 int
150 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
151 {
152 
153 	PROC_ACTION(set_fpregs(td, fpregs));
154 }
155 
156 #ifdef COMPAT_FREEBSD32
157 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
158 int
159 proc_read_regs32(struct thread *td, struct reg32 *regs32)
160 {
161 
162 	PROC_ACTION(fill_regs32(td, regs32));
163 }
164 
165 int
166 proc_write_regs32(struct thread *td, struct reg32 *regs32)
167 {
168 
169 	PROC_ACTION(set_regs32(td, regs32));
170 }
171 
172 int
173 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
174 {
175 
176 	PROC_ACTION(fill_dbregs32(td, dbregs32));
177 }
178 
179 int
180 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
181 {
182 
183 	PROC_ACTION(set_dbregs32(td, dbregs32));
184 }
185 
186 int
187 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
188 {
189 
190 	PROC_ACTION(fill_fpregs32(td, fpregs32));
191 }
192 
193 int
194 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
195 {
196 
197 	PROC_ACTION(set_fpregs32(td, fpregs32));
198 }
199 #endif
200 
201 int
202 proc_sstep(struct thread *td)
203 {
204 
205 	PROC_ACTION(ptrace_single_step(td));
206 }
207 
208 int
209 proc_rwmem(struct proc *p, struct uio *uio)
210 {
211 	vm_map_t map;
212 	vm_offset_t pageno;		/* page number */
213 	vm_prot_t reqprot;
214 	int error, fault_flags, page_offset, writing;
215 
216 	/*
217 	 * Assert that someone has locked this vmspace.  (Should be
218 	 * curthread but we can't assert that.)  This keeps the process
219 	 * from exiting out from under us until this operation completes.
220 	 */
221 	PROC_ASSERT_HELD(p);
222 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
223 
224 	/*
225 	 * The map we want...
226 	 */
227 	map = &p->p_vmspace->vm_map;
228 
229 	/*
230 	 * If we are writing, then we request vm_fault() to create a private
231 	 * copy of each page.  Since these copies will not be writeable by the
232 	 * process, we must explicity request that they be dirtied.
233 	 */
234 	writing = uio->uio_rw == UIO_WRITE;
235 	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
236 	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
237 
238 	/*
239 	 * Only map in one page at a time.  We don't have to, but it
240 	 * makes things easier.  This way is trivial - right?
241 	 */
242 	do {
243 		vm_offset_t uva;
244 		u_int len;
245 		vm_page_t m;
246 
247 		uva = (vm_offset_t)uio->uio_offset;
248 
249 		/*
250 		 * Get the page number of this segment.
251 		 */
252 		pageno = trunc_page(uva);
253 		page_offset = uva - pageno;
254 
255 		/*
256 		 * How many bytes to copy
257 		 */
258 		len = min(PAGE_SIZE - page_offset, uio->uio_resid);
259 
260 		/*
261 		 * Fault and hold the page on behalf of the process.
262 		 */
263 		error = vm_fault(map, pageno, reqprot, fault_flags, &m);
264 		if (error != KERN_SUCCESS) {
265 			if (error == KERN_RESOURCE_SHORTAGE)
266 				error = ENOMEM;
267 			else
268 				error = EFAULT;
269 			break;
270 		}
271 
272 		/*
273 		 * Now do the i/o move.
274 		 */
275 		error = uiomove_fromphys(&m, page_offset, len, uio);
276 
277 		/* Make the I-cache coherent for breakpoints. */
278 		if (writing && error == 0) {
279 			vm_map_lock_read(map);
280 			if (vm_map_check_protection(map, pageno, pageno +
281 			    PAGE_SIZE, VM_PROT_EXECUTE))
282 				vm_sync_icache(map, uva, len);
283 			vm_map_unlock_read(map);
284 		}
285 
286 		/*
287 		 * Release the page.
288 		 */
289 		vm_page_unwire(m, PQ_ACTIVE);
290 
291 	} while (error == 0 && uio->uio_resid > 0);
292 
293 	return (error);
294 }
295 
296 static ssize_t
297 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
298     size_t len, enum uio_rw rw)
299 {
300 	struct iovec iov;
301 	struct uio uio;
302 	ssize_t slen;
303 
304 	MPASS(len < SSIZE_MAX);
305 	slen = (ssize_t)len;
306 
307 	iov.iov_base = (caddr_t)buf;
308 	iov.iov_len = len;
309 	uio.uio_iov = &iov;
310 	uio.uio_iovcnt = 1;
311 	uio.uio_offset = va;
312 	uio.uio_resid = slen;
313 	uio.uio_segflg = UIO_SYSSPACE;
314 	uio.uio_rw = rw;
315 	uio.uio_td = td;
316 	proc_rwmem(p, &uio);
317 	if (uio.uio_resid == slen)
318 		return (-1);
319 	return (slen - uio.uio_resid);
320 }
321 
322 ssize_t
323 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
324     size_t len)
325 {
326 
327 	return (proc_iop(td, p, va, buf, len, UIO_READ));
328 }
329 
330 ssize_t
331 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
332     size_t len)
333 {
334 
335 	return (proc_iop(td, p, va, buf, len, UIO_WRITE));
336 }
337 
338 static int
339 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
340 {
341 	struct vattr vattr;
342 	vm_map_t map;
343 	vm_map_entry_t entry;
344 	vm_object_t obj, tobj, lobj;
345 	struct vmspace *vm;
346 	struct vnode *vp;
347 	char *freepath, *fullpath;
348 	u_int pathlen;
349 	int error, index;
350 
351 	error = 0;
352 	obj = NULL;
353 
354 	vm = vmspace_acquire_ref(p);
355 	map = &vm->vm_map;
356 	vm_map_lock_read(map);
357 
358 	do {
359 		KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
360 		    ("Submap in map header"));
361 		index = 0;
362 		VM_MAP_ENTRY_FOREACH(entry, map) {
363 			if (index >= pve->pve_entry &&
364 			    (entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
365 				break;
366 			index++;
367 		}
368 		if (index < pve->pve_entry) {
369 			error = EINVAL;
370 			break;
371 		}
372 		if (entry == &map->header) {
373 			error = ENOENT;
374 			break;
375 		}
376 
377 		/* We got an entry. */
378 		pve->pve_entry = index + 1;
379 		pve->pve_timestamp = map->timestamp;
380 		pve->pve_start = entry->start;
381 		pve->pve_end = entry->end - 1;
382 		pve->pve_offset = entry->offset;
383 		pve->pve_prot = entry->protection;
384 
385 		/* Backing object's path needed? */
386 		if (pve->pve_pathlen == 0)
387 			break;
388 
389 		pathlen = pve->pve_pathlen;
390 		pve->pve_pathlen = 0;
391 
392 		obj = entry->object.vm_object;
393 		if (obj != NULL)
394 			VM_OBJECT_RLOCK(obj);
395 	} while (0);
396 
397 	vm_map_unlock_read(map);
398 
399 	pve->pve_fsid = VNOVAL;
400 	pve->pve_fileid = VNOVAL;
401 
402 	if (error == 0 && obj != NULL) {
403 		lobj = obj;
404 		for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
405 			if (tobj != obj)
406 				VM_OBJECT_RLOCK(tobj);
407 			if (lobj != obj)
408 				VM_OBJECT_RUNLOCK(lobj);
409 			lobj = tobj;
410 			pve->pve_offset += tobj->backing_object_offset;
411 		}
412 		vp = vm_object_vnode(lobj);
413 		if (vp != NULL)
414 			vref(vp);
415 		if (lobj != obj)
416 			VM_OBJECT_RUNLOCK(lobj);
417 		VM_OBJECT_RUNLOCK(obj);
418 
419 		if (vp != NULL) {
420 			freepath = NULL;
421 			fullpath = NULL;
422 			vn_fullpath(vp, &fullpath, &freepath);
423 			vn_lock(vp, LK_SHARED | LK_RETRY);
424 			if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
425 				pve->pve_fileid = vattr.va_fileid;
426 				pve->pve_fsid = vattr.va_fsid;
427 			}
428 			vput(vp);
429 
430 			if (fullpath != NULL) {
431 				pve->pve_pathlen = strlen(fullpath) + 1;
432 				if (pve->pve_pathlen <= pathlen) {
433 					error = copyout(fullpath, pve->pve_path,
434 					    pve->pve_pathlen);
435 				} else
436 					error = ENAMETOOLONG;
437 			}
438 			if (freepath != NULL)
439 				free(freepath, M_TEMP);
440 		}
441 	}
442 	vmspace_free(vm);
443 	if (error == 0)
444 		CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
445 		    p->p_pid, pve->pve_entry, pve->pve_start);
446 
447 	return (error);
448 }
449 
450 /*
451  * Process debugging system call.
452  */
453 #ifndef _SYS_SYSPROTO_H_
454 struct ptrace_args {
455 	int	req;
456 	pid_t	pid;
457 	caddr_t	addr;
458 	int	data;
459 };
460 #endif
461 
462 int
463 sys_ptrace(struct thread *td, struct ptrace_args *uap)
464 {
465 	/*
466 	 * XXX this obfuscation is to reduce stack usage, but the register
467 	 * structs may be too large to put on the stack anyway.
468 	 */
469 	union {
470 		struct ptrace_io_desc piod;
471 		struct ptrace_lwpinfo pl;
472 		struct ptrace_vm_entry pve;
473 		struct ptrace_coredump pc;
474 		struct dbreg dbreg;
475 		struct fpreg fpreg;
476 		struct reg reg;
477 		char args[sizeof(td->td_sa.args)];
478 		struct ptrace_sc_ret psr;
479 		int ptevents;
480 	} r;
481 	void *addr;
482 	int error = 0;
483 
484 	AUDIT_ARG_PID(uap->pid);
485 	AUDIT_ARG_CMD(uap->req);
486 	AUDIT_ARG_VALUE(uap->data);
487 	addr = &r;
488 	switch (uap->req) {
489 	case PT_GET_EVENT_MASK:
490 	case PT_LWPINFO:
491 	case PT_GET_SC_ARGS:
492 	case PT_GET_SC_RET:
493 		break;
494 	case PT_GETREGS:
495 		bzero(&r.reg, sizeof(r.reg));
496 		break;
497 	case PT_GETFPREGS:
498 		bzero(&r.fpreg, sizeof(r.fpreg));
499 		break;
500 	case PT_GETDBREGS:
501 		bzero(&r.dbreg, sizeof(r.dbreg));
502 		break;
503 	case PT_SETREGS:
504 		error = copyin(uap->addr, &r.reg, sizeof(r.reg));
505 		break;
506 	case PT_SETFPREGS:
507 		error = copyin(uap->addr, &r.fpreg, sizeof(r.fpreg));
508 		break;
509 	case PT_SETDBREGS:
510 		error = copyin(uap->addr, &r.dbreg, sizeof(r.dbreg));
511 		break;
512 	case PT_SET_EVENT_MASK:
513 		if (uap->data != sizeof(r.ptevents))
514 			error = EINVAL;
515 		else
516 			error = copyin(uap->addr, &r.ptevents, uap->data);
517 		break;
518 	case PT_IO:
519 		error = copyin(uap->addr, &r.piod, sizeof(r.piod));
520 		break;
521 	case PT_VM_ENTRY:
522 		error = copyin(uap->addr, &r.pve, sizeof(r.pve));
523 		break;
524 	case PT_COREDUMP:
525 		if (uap->data != sizeof(r.pc))
526 			error = EINVAL;
527 		else
528 			error = copyin(uap->addr, &r.pc, uap->data);
529 		break;
530 	case PT_GET_SC_ARGS_ALL:
531 		error = EINVAL;
532 		break;
533 	default:
534 		addr = uap->addr;
535 		break;
536 	}
537 	if (error)
538 		return (error);
539 
540 	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
541 	if (error)
542 		return (error);
543 
544 	switch (uap->req) {
545 	case PT_VM_ENTRY:
546 		error = copyout(&r.pve, uap->addr, sizeof(r.pve));
547 		break;
548 	case PT_IO:
549 		error = copyout(&r.piod, uap->addr, sizeof(r.piod));
550 		break;
551 	case PT_GETREGS:
552 		error = copyout(&r.reg, uap->addr, sizeof(r.reg));
553 		break;
554 	case PT_GETFPREGS:
555 		error = copyout(&r.fpreg, uap->addr, sizeof(r.fpreg));
556 		break;
557 	case PT_GETDBREGS:
558 		error = copyout(&r.dbreg, uap->addr, sizeof(r.dbreg));
559 		break;
560 	case PT_GET_EVENT_MASK:
561 		/* NB: The size in uap->data is validated in kern_ptrace(). */
562 		error = copyout(&r.ptevents, uap->addr, uap->data);
563 		break;
564 	case PT_LWPINFO:
565 		/* NB: The size in uap->data is validated in kern_ptrace(). */
566 		error = copyout(&r.pl, uap->addr, uap->data);
567 		break;
568 	case PT_GET_SC_ARGS:
569 		error = copyout(r.args, uap->addr, MIN(uap->data,
570 		    sizeof(r.args)));
571 		break;
572 	case PT_GET_SC_RET:
573 		error = copyout(&r.psr, uap->addr, MIN(uap->data,
574 		    sizeof(r.psr)));
575 		break;
576 	}
577 
578 	return (error);
579 }
580 
581 #ifdef COMPAT_FREEBSD32
582 /*
583  *   PROC_READ(regs, td2, addr);
584  * becomes either:
585  *   proc_read_regs(td2, addr);
586  * or
587  *   proc_read_regs32(td2, addr);
588  * .. except this is done at runtime.  There is an additional
589  * complication in that PROC_WRITE disallows 32 bit consumers
590  * from writing to 64 bit address space targets.
591  */
592 #define	PROC_READ(w, t, a)	wrap32 ? \
593 	proc_read_ ## w ## 32(t, a) : \
594 	proc_read_ ## w (t, a)
595 #define	PROC_WRITE(w, t, a)	wrap32 ? \
596 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
597 	proc_write_ ## w (t, a)
598 #else
599 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
600 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
601 #endif
602 
603 void
604 proc_set_traced(struct proc *p, bool stop)
605 {
606 
607 	sx_assert(&proctree_lock, SX_XLOCKED);
608 	PROC_LOCK_ASSERT(p, MA_OWNED);
609 	p->p_flag |= P_TRACED;
610 	if (stop)
611 		p->p_flag2 |= P2_PTRACE_FSTP;
612 	p->p_ptevents = PTRACE_DEFAULT;
613 }
614 
615 void
616 ptrace_unsuspend(struct proc *p)
617 {
618 	PROC_LOCK_ASSERT(p, MA_OWNED);
619 
620 	PROC_SLOCK(p);
621 	p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
622 	thread_unsuspend(p);
623 	PROC_SUNLOCK(p);
624 	itimer_proc_continue(p);
625 	kqtimer_proc_continue(p);
626 }
627 
628 static int
629 proc_can_ptrace(struct thread *td, struct proc *p)
630 {
631 	int error;
632 
633 	PROC_LOCK_ASSERT(p, MA_OWNED);
634 
635 	if ((p->p_flag & P_WEXIT) != 0)
636 		return (ESRCH);
637 
638 	if ((error = p_cansee(td, p)) != 0)
639 		return (error);
640 	if ((error = p_candebug(td, p)) != 0)
641 		return (error);
642 
643 	/* not being traced... */
644 	if ((p->p_flag & P_TRACED) == 0)
645 		return (EPERM);
646 
647 	/* not being traced by YOU */
648 	if (p->p_pptr != td->td_proc)
649 		return (EBUSY);
650 
651 	/* not currently stopped */
652 	if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
653 	    p->p_suspcount != p->p_numthreads  ||
654 	    (p->p_flag & P_WAITED) == 0)
655 		return (EBUSY);
656 
657 	return (0);
658 }
659 
660 static struct thread *
661 ptrace_sel_coredump_thread(struct proc *p)
662 {
663 	struct thread *td2;
664 
665 	PROC_LOCK_ASSERT(p, MA_OWNED);
666 	MPASS((p->p_flag & P_STOPPED_TRACE) != 0);
667 
668 	FOREACH_THREAD_IN_PROC(p, td2) {
669 		if ((td2->td_dbgflags & TDB_SSWITCH) != 0)
670 			return (td2);
671 	}
672 	return (NULL);
673 }
674 
675 int
676 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
677 {
678 	struct iovec iov;
679 	struct uio uio;
680 	struct proc *curp, *p, *pp;
681 	struct thread *td2 = NULL, *td3;
682 	struct ptrace_io_desc *piod = NULL;
683 	struct ptrace_lwpinfo *pl;
684 	struct ptrace_sc_ret *psr;
685 	struct file *fp;
686 	struct ptrace_coredump *pc;
687 	struct thr_coredump_req *tcq;
688 	int error, num, tmp;
689 	lwpid_t tid = 0, *buf;
690 #ifdef COMPAT_FREEBSD32
691 	int wrap32 = 0, safe = 0;
692 #endif
693 	bool proctree_locked, p2_req_set;
694 
695 	curp = td->td_proc;
696 	proctree_locked = false;
697 	p2_req_set = false;
698 
699 	/* Lock proctree before locking the process. */
700 	switch (req) {
701 	case PT_TRACE_ME:
702 	case PT_ATTACH:
703 	case PT_STEP:
704 	case PT_CONTINUE:
705 	case PT_TO_SCE:
706 	case PT_TO_SCX:
707 	case PT_SYSCALL:
708 	case PT_FOLLOW_FORK:
709 	case PT_LWP_EVENTS:
710 	case PT_GET_EVENT_MASK:
711 	case PT_SET_EVENT_MASK:
712 	case PT_DETACH:
713 	case PT_GET_SC_ARGS:
714 	case PT_GET_SC_ARGS_ALL:
715 		sx_xlock(&proctree_lock);
716 		proctree_locked = true;
717 		break;
718 	default:
719 		break;
720 	}
721 
722 	if (req == PT_TRACE_ME) {
723 		p = td->td_proc;
724 		PROC_LOCK(p);
725 	} else {
726 		if (pid <= PID_MAX) {
727 			if ((p = pfind(pid)) == NULL) {
728 				if (proctree_locked)
729 					sx_xunlock(&proctree_lock);
730 				return (ESRCH);
731 			}
732 		} else {
733 			td2 = tdfind(pid, -1);
734 			if (td2 == NULL) {
735 				if (proctree_locked)
736 					sx_xunlock(&proctree_lock);
737 				return (ESRCH);
738 			}
739 			p = td2->td_proc;
740 			tid = pid;
741 			pid = p->p_pid;
742 		}
743 	}
744 	AUDIT_ARG_PROCESS(p);
745 
746 	if ((p->p_flag & P_WEXIT) != 0) {
747 		error = ESRCH;
748 		goto fail;
749 	}
750 	if ((error = p_cansee(td, p)) != 0)
751 		goto fail;
752 
753 	if ((error = p_candebug(td, p)) != 0)
754 		goto fail;
755 
756 	/*
757 	 * System processes can't be debugged.
758 	 */
759 	if ((p->p_flag & P_SYSTEM) != 0) {
760 		error = EINVAL;
761 		goto fail;
762 	}
763 
764 	if (tid == 0) {
765 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
766 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
767 			td2 = p->p_xthread;
768 		} else {
769 			td2 = FIRST_THREAD_IN_PROC(p);
770 		}
771 		tid = td2->td_tid;
772 	}
773 
774 #ifdef COMPAT_FREEBSD32
775 	/*
776 	 * Test if we're a 32 bit client and what the target is.
777 	 * Set the wrap controls accordingly.
778 	 */
779 	if (SV_CURPROC_FLAG(SV_ILP32)) {
780 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
781 			safe = 1;
782 		wrap32 = 1;
783 	}
784 #endif
785 	/*
786 	 * Permissions check
787 	 */
788 	switch (req) {
789 	case PT_TRACE_ME:
790 		/*
791 		 * Always legal, when there is a parent process which
792 		 * could trace us.  Otherwise, reject.
793 		 */
794 		if ((p->p_flag & P_TRACED) != 0) {
795 			error = EBUSY;
796 			goto fail;
797 		}
798 		if (p->p_pptr == initproc) {
799 			error = EPERM;
800 			goto fail;
801 		}
802 		break;
803 
804 	case PT_ATTACH:
805 		/* Self */
806 		if (p == td->td_proc) {
807 			error = EINVAL;
808 			goto fail;
809 		}
810 
811 		/* Already traced */
812 		if (p->p_flag & P_TRACED) {
813 			error = EBUSY;
814 			goto fail;
815 		}
816 
817 		/* Can't trace an ancestor if you're being traced. */
818 		if (curp->p_flag & P_TRACED) {
819 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
820 				if (pp == p) {
821 					error = EINVAL;
822 					goto fail;
823 				}
824 			}
825 		}
826 
827 		/* OK */
828 		break;
829 
830 	case PT_CLEARSTEP:
831 		/* Allow thread to clear single step for itself */
832 		if (td->td_tid == tid)
833 			break;
834 
835 		/* FALLTHROUGH */
836 	default:
837 		/*
838 		 * Check for ptrace eligibility before waiting for
839 		 * holds to drain.
840 		 */
841 		error = proc_can_ptrace(td, p);
842 		if (error != 0)
843 			goto fail;
844 
845 		/*
846 		 * Block parallel ptrace requests.  Most important, do
847 		 * not allow other thread in debugger to continue the
848 		 * debuggee until coredump finished.
849 		 */
850 		while ((p->p_flag2 & P2_PTRACEREQ) != 0) {
851 			if (proctree_locked)
852 				sx_xunlock(&proctree_lock);
853 			error = msleep(&p->p_flag2, &p->p_mtx, PPAUSE | PCATCH |
854 			    (proctree_locked ? PDROP : 0), "pptrace", 0);
855 			if (proctree_locked) {
856 				sx_xlock(&proctree_lock);
857 				PROC_LOCK(p);
858 			}
859 			if (error == 0 && td2->td_proc != p)
860 				error = ESRCH;
861 			if (error == 0)
862 				error = proc_can_ptrace(td, p);
863 			if (error != 0)
864 				goto fail;
865 		}
866 
867 		/* Ok */
868 		break;
869 	}
870 
871 	/*
872 	 * Keep this process around and request parallel ptrace()
873 	 * request to wait until we finish this request.
874 	 */
875 	MPASS((p->p_flag2 & P2_PTRACEREQ) == 0);
876 	p->p_flag2 |= P2_PTRACEREQ;
877 	p2_req_set = true;
878 	_PHOLD(p);
879 
880 	/*
881 	 * Actually do the requests
882 	 */
883 
884 	td->td_retval[0] = 0;
885 
886 	switch (req) {
887 	case PT_TRACE_ME:
888 		/* set my trace flag and "owner" so it can read/write me */
889 		proc_set_traced(p, false);
890 		if (p->p_flag & P_PPWAIT)
891 			p->p_flag |= P_PPTRACE;
892 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
893 		break;
894 
895 	case PT_ATTACH:
896 		/* security check done above */
897 		/*
898 		 * It would be nice if the tracing relationship was separate
899 		 * from the parent relationship but that would require
900 		 * another set of links in the proc struct or for "wait"
901 		 * to scan the entire proc table.  To make life easier,
902 		 * we just re-parent the process we're trying to trace.
903 		 * The old parent is remembered so we can put things back
904 		 * on a "detach".
905 		 */
906 		proc_set_traced(p, true);
907 		proc_reparent(p, td->td_proc, false);
908 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
909 		    p->p_oppid);
910 
911 		sx_xunlock(&proctree_lock);
912 		proctree_locked = false;
913 		MPASS(p->p_xthread == NULL);
914 		MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
915 
916 		/*
917 		 * If already stopped due to a stop signal, clear the
918 		 * existing stop before triggering a traced SIGSTOP.
919 		 */
920 		if ((p->p_flag & P_STOPPED_SIG) != 0) {
921 			PROC_SLOCK(p);
922 			p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
923 			thread_unsuspend(p);
924 			PROC_SUNLOCK(p);
925 		}
926 
927 		kern_psignal(p, SIGSTOP);
928 		break;
929 
930 	case PT_CLEARSTEP:
931 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
932 		    p->p_pid);
933 		error = ptrace_clear_single_step(td2);
934 		break;
935 
936 	case PT_SETSTEP:
937 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
938 		    p->p_pid);
939 		error = ptrace_single_step(td2);
940 		break;
941 
942 	case PT_SUSPEND:
943 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
944 		    p->p_pid);
945 		td2->td_dbgflags |= TDB_SUSPEND;
946 		thread_lock(td2);
947 		td2->td_flags |= TDF_NEEDSUSPCHK;
948 		thread_unlock(td2);
949 		break;
950 
951 	case PT_RESUME:
952 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
953 		    p->p_pid);
954 		td2->td_dbgflags &= ~TDB_SUSPEND;
955 		break;
956 
957 	case PT_FOLLOW_FORK:
958 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
959 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
960 		    data ? "enabled" : "disabled");
961 		if (data)
962 			p->p_ptevents |= PTRACE_FORK;
963 		else
964 			p->p_ptevents &= ~PTRACE_FORK;
965 		break;
966 
967 	case PT_LWP_EVENTS:
968 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
969 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
970 		    data ? "enabled" : "disabled");
971 		if (data)
972 			p->p_ptevents |= PTRACE_LWP;
973 		else
974 			p->p_ptevents &= ~PTRACE_LWP;
975 		break;
976 
977 	case PT_GET_EVENT_MASK:
978 		if (data != sizeof(p->p_ptevents)) {
979 			error = EINVAL;
980 			break;
981 		}
982 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
983 		    p->p_ptevents);
984 		*(int *)addr = p->p_ptevents;
985 		break;
986 
987 	case PT_SET_EVENT_MASK:
988 		if (data != sizeof(p->p_ptevents)) {
989 			error = EINVAL;
990 			break;
991 		}
992 		tmp = *(int *)addr;
993 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
994 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
995 			error = EINVAL;
996 			break;
997 		}
998 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
999 		    p->p_pid, p->p_ptevents, tmp);
1000 		p->p_ptevents = tmp;
1001 		break;
1002 
1003 	case PT_GET_SC_ARGS:
1004 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1005 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1006 #ifdef COMPAT_FREEBSD32
1007 		    || (wrap32 && !safe)
1008 #endif
1009 		    ) {
1010 			error = EINVAL;
1011 			break;
1012 		}
1013 		bzero(addr, sizeof(td2->td_sa.args));
1014 		bcopy(td2->td_sa.args, addr, td2->td_sa.callp->sy_narg *
1015 		    sizeof(register_t));
1016 		break;
1017 
1018 	case PT_GET_SC_ARGS_ALL:
1019 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS_ALL: pid %d", p->p_pid);
1020 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1021 #ifdef COMPAT_FREEBSD32
1022 		    || (wrap32 && !safe)
1023 #endif
1024 		    ) {
1025 			error = EINVAL;
1026 			break;
1027 		}
1028 		bcopy(td2->td_sa.args, addr, sizeof(td2->td_sa.args));
1029 		break;
1030 
1031 	case PT_GET_SC_RET:
1032 		if ((td2->td_dbgflags & (TDB_SCX)) == 0
1033 #ifdef COMPAT_FREEBSD32
1034 		    || (wrap32 && !safe)
1035 #endif
1036 		    ) {
1037 			error = EINVAL;
1038 			break;
1039 		}
1040 		psr = addr;
1041 		bzero(psr, sizeof(*psr));
1042 		psr->sr_error = td2->td_errno;
1043 		if (psr->sr_error == 0) {
1044 			psr->sr_retval[0] = td2->td_retval[0];
1045 			psr->sr_retval[1] = td2->td_retval[1];
1046 		}
1047 		CTR4(KTR_PTRACE,
1048 		    "PT_GET_SC_RET: pid %d error %d retval %#lx,%#lx",
1049 		    p->p_pid, psr->sr_error, psr->sr_retval[0],
1050 		    psr->sr_retval[1]);
1051 		break;
1052 
1053 	case PT_STEP:
1054 	case PT_CONTINUE:
1055 	case PT_TO_SCE:
1056 	case PT_TO_SCX:
1057 	case PT_SYSCALL:
1058 	case PT_DETACH:
1059 		/* Zero means do not send any signal */
1060 		if (data < 0 || data > _SIG_MAXSIG) {
1061 			error = EINVAL;
1062 			break;
1063 		}
1064 
1065 		switch (req) {
1066 		case PT_STEP:
1067 			CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1068 			    td2->td_tid, p->p_pid, data);
1069 			error = ptrace_single_step(td2);
1070 			if (error)
1071 				goto out;
1072 			break;
1073 		case PT_CONTINUE:
1074 		case PT_TO_SCE:
1075 		case PT_TO_SCX:
1076 		case PT_SYSCALL:
1077 			if (addr != (void *)1) {
1078 				error = ptrace_set_pc(td2,
1079 				    (u_long)(uintfptr_t)addr);
1080 				if (error)
1081 					goto out;
1082 			}
1083 			switch (req) {
1084 			case PT_TO_SCE:
1085 				p->p_ptevents |= PTRACE_SCE;
1086 				CTR4(KTR_PTRACE,
1087 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1088 				    p->p_pid, p->p_ptevents,
1089 				    (u_long)(uintfptr_t)addr, data);
1090 				break;
1091 			case PT_TO_SCX:
1092 				p->p_ptevents |= PTRACE_SCX;
1093 				CTR4(KTR_PTRACE,
1094 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1095 				    p->p_pid, p->p_ptevents,
1096 				    (u_long)(uintfptr_t)addr, data);
1097 				break;
1098 			case PT_SYSCALL:
1099 				p->p_ptevents |= PTRACE_SYSCALL;
1100 				CTR4(KTR_PTRACE,
1101 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1102 				    p->p_pid, p->p_ptevents,
1103 				    (u_long)(uintfptr_t)addr, data);
1104 				break;
1105 			case PT_CONTINUE:
1106 				CTR3(KTR_PTRACE,
1107 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1108 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1109 				break;
1110 			}
1111 			break;
1112 		case PT_DETACH:
1113 			/*
1114 			 * Clear P_TRACED before reparenting
1115 			 * a detached process back to its original
1116 			 * parent.  Otherwise the debugee will be set
1117 			 * as an orphan of the debugger.
1118 			 */
1119 			p->p_flag &= ~(P_TRACED | P_WAITED);
1120 
1121 			/*
1122 			 * Reset the process parent.
1123 			 */
1124 			if (p->p_oppid != p->p_pptr->p_pid) {
1125 				PROC_LOCK(p->p_pptr);
1126 				sigqueue_take(p->p_ksi);
1127 				PROC_UNLOCK(p->p_pptr);
1128 
1129 				pp = proc_realparent(p);
1130 				proc_reparent(p, pp, false);
1131 				if (pp == initproc)
1132 					p->p_sigparent = SIGCHLD;
1133 				CTR3(KTR_PTRACE,
1134 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1135 				    p->p_pid, pp->p_pid, data);
1136 			} else {
1137 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1138 				    p->p_pid, data);
1139 			}
1140 
1141 			p->p_ptevents = 0;
1142 			FOREACH_THREAD_IN_PROC(p, td3) {
1143 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1144 					sigqueue_delete(&td3->td_sigqueue,
1145 					    SIGSTOP);
1146 				}
1147 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1148 				    TDB_SUSPEND);
1149 			}
1150 
1151 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1152 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1153 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1154 			}
1155 
1156 			/* should we send SIGCHLD? */
1157 			/* childproc_continued(p); */
1158 			break;
1159 		}
1160 
1161 		sx_xunlock(&proctree_lock);
1162 		proctree_locked = false;
1163 
1164 	sendsig:
1165 		MPASS(!proctree_locked);
1166 
1167 		/*
1168 		 * Clear the pending event for the thread that just
1169 		 * reported its event (p_xthread).  This may not be
1170 		 * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1171 		 * the debugger is resuming a different thread.
1172 		 *
1173 		 * Deliver any pending signal via the reporting thread.
1174 		 */
1175 		MPASS(p->p_xthread != NULL);
1176 		p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1177 		p->p_xthread->td_xsig = data;
1178 		p->p_xthread = NULL;
1179 		p->p_xsig = data;
1180 
1181 		/*
1182 		 * P_WKILLED is insurance that a PT_KILL/SIGKILL
1183 		 * always works immediately, even if another thread is
1184 		 * unsuspended first and attempts to handle a
1185 		 * different signal or if the POSIX.1b style signal
1186 		 * queue cannot accommodate any new signals.
1187 		 */
1188 		if (data == SIGKILL)
1189 			proc_wkilled(p);
1190 
1191 		/*
1192 		 * Unsuspend all threads.  To leave a thread
1193 		 * suspended, use PT_SUSPEND to suspend it before
1194 		 * continuing the process.
1195 		 */
1196 		ptrace_unsuspend(p);
1197 		break;
1198 
1199 	case PT_WRITE_I:
1200 	case PT_WRITE_D:
1201 		td2->td_dbgflags |= TDB_USERWR;
1202 		PROC_UNLOCK(p);
1203 		error = 0;
1204 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1205 		    sizeof(int)) != sizeof(int))
1206 			error = ENOMEM;
1207 		else
1208 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1209 			    p->p_pid, addr, data);
1210 		PROC_LOCK(p);
1211 		break;
1212 
1213 	case PT_READ_I:
1214 	case PT_READ_D:
1215 		PROC_UNLOCK(p);
1216 		error = tmp = 0;
1217 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1218 		    sizeof(int)) != sizeof(int))
1219 			error = ENOMEM;
1220 		else
1221 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1222 			    p->p_pid, addr, tmp);
1223 		td->td_retval[0] = tmp;
1224 		PROC_LOCK(p);
1225 		break;
1226 
1227 	case PT_IO:
1228 		piod = addr;
1229 		iov.iov_base = piod->piod_addr;
1230 		iov.iov_len = piod->piod_len;
1231 		uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1232 		uio.uio_resid = piod->piod_len;
1233 		uio.uio_iov = &iov;
1234 		uio.uio_iovcnt = 1;
1235 		uio.uio_segflg = UIO_USERSPACE;
1236 		uio.uio_td = td;
1237 		switch (piod->piod_op) {
1238 		case PIOD_READ_D:
1239 		case PIOD_READ_I:
1240 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1241 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1242 			uio.uio_rw = UIO_READ;
1243 			break;
1244 		case PIOD_WRITE_D:
1245 		case PIOD_WRITE_I:
1246 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1247 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1248 			td2->td_dbgflags |= TDB_USERWR;
1249 			uio.uio_rw = UIO_WRITE;
1250 			break;
1251 		default:
1252 			error = EINVAL;
1253 			goto out;
1254 		}
1255 		PROC_UNLOCK(p);
1256 		error = proc_rwmem(p, &uio);
1257 		piod->piod_len -= uio.uio_resid;
1258 		PROC_LOCK(p);
1259 		break;
1260 
1261 	case PT_KILL:
1262 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1263 		data = SIGKILL;
1264 		goto sendsig;	/* in PT_CONTINUE above */
1265 
1266 	case PT_SETREGS:
1267 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1268 		    p->p_pid);
1269 		td2->td_dbgflags |= TDB_USERWR;
1270 		error = PROC_WRITE(regs, td2, addr);
1271 		break;
1272 
1273 	case PT_GETREGS:
1274 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1275 		    p->p_pid);
1276 		error = PROC_READ(regs, td2, addr);
1277 		break;
1278 
1279 	case PT_SETFPREGS:
1280 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1281 		    p->p_pid);
1282 		td2->td_dbgflags |= TDB_USERWR;
1283 		error = PROC_WRITE(fpregs, td2, addr);
1284 		break;
1285 
1286 	case PT_GETFPREGS:
1287 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1288 		    p->p_pid);
1289 		error = PROC_READ(fpregs, td2, addr);
1290 		break;
1291 
1292 	case PT_SETDBREGS:
1293 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1294 		    p->p_pid);
1295 		td2->td_dbgflags |= TDB_USERWR;
1296 		error = PROC_WRITE(dbregs, td2, addr);
1297 		break;
1298 
1299 	case PT_GETDBREGS:
1300 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1301 		    p->p_pid);
1302 		error = PROC_READ(dbregs, td2, addr);
1303 		break;
1304 
1305 	case PT_LWPINFO:
1306 		if (data <= 0 || data > sizeof(*pl)) {
1307 			error = EINVAL;
1308 			break;
1309 		}
1310 		pl = addr;
1311 		bzero(pl, sizeof(*pl));
1312 		pl->pl_lwpid = td2->td_tid;
1313 		pl->pl_event = PL_EVENT_NONE;
1314 		pl->pl_flags = 0;
1315 		if (td2->td_dbgflags & TDB_XSIG) {
1316 			pl->pl_event = PL_EVENT_SIGNAL;
1317 			if (td2->td_si.si_signo != 0 &&
1318 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1319 			    + sizeof(pl->pl_siginfo)){
1320 				pl->pl_flags |= PL_FLAG_SI;
1321 				pl->pl_siginfo = td2->td_si;
1322 			}
1323 		}
1324 		if (td2->td_dbgflags & TDB_SCE)
1325 			pl->pl_flags |= PL_FLAG_SCE;
1326 		else if (td2->td_dbgflags & TDB_SCX)
1327 			pl->pl_flags |= PL_FLAG_SCX;
1328 		if (td2->td_dbgflags & TDB_EXEC)
1329 			pl->pl_flags |= PL_FLAG_EXEC;
1330 		if (td2->td_dbgflags & TDB_FORK) {
1331 			pl->pl_flags |= PL_FLAG_FORKED;
1332 			pl->pl_child_pid = td2->td_dbg_forked;
1333 			if (td2->td_dbgflags & TDB_VFORK)
1334 				pl->pl_flags |= PL_FLAG_VFORKED;
1335 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1336 		    TDB_VFORK)
1337 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1338 		if (td2->td_dbgflags & TDB_CHILD)
1339 			pl->pl_flags |= PL_FLAG_CHILD;
1340 		if (td2->td_dbgflags & TDB_BORN)
1341 			pl->pl_flags |= PL_FLAG_BORN;
1342 		if (td2->td_dbgflags & TDB_EXIT)
1343 			pl->pl_flags |= PL_FLAG_EXITED;
1344 		pl->pl_sigmask = td2->td_sigmask;
1345 		pl->pl_siglist = td2->td_siglist;
1346 		strcpy(pl->pl_tdname, td2->td_name);
1347 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1348 			pl->pl_syscall_code = td2->td_sa.code;
1349 			pl->pl_syscall_narg = td2->td_sa.callp->sy_narg;
1350 		} else {
1351 			pl->pl_syscall_code = 0;
1352 			pl->pl_syscall_narg = 0;
1353 		}
1354 		CTR6(KTR_PTRACE,
1355     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1356 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1357 		    pl->pl_child_pid, pl->pl_syscall_code);
1358 		break;
1359 
1360 	case PT_GETNUMLWPS:
1361 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1362 		    p->p_numthreads);
1363 		td->td_retval[0] = p->p_numthreads;
1364 		break;
1365 
1366 	case PT_GETLWPLIST:
1367 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1368 		    p->p_pid, data, p->p_numthreads);
1369 		if (data <= 0) {
1370 			error = EINVAL;
1371 			break;
1372 		}
1373 		num = imin(p->p_numthreads, data);
1374 		PROC_UNLOCK(p);
1375 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1376 		tmp = 0;
1377 		PROC_LOCK(p);
1378 		FOREACH_THREAD_IN_PROC(p, td2) {
1379 			if (tmp >= num)
1380 				break;
1381 			buf[tmp++] = td2->td_tid;
1382 		}
1383 		PROC_UNLOCK(p);
1384 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1385 		free(buf, M_TEMP);
1386 		if (!error)
1387 			td->td_retval[0] = tmp;
1388 		PROC_LOCK(p);
1389 		break;
1390 
1391 	case PT_VM_TIMESTAMP:
1392 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1393 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1394 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1395 		break;
1396 
1397 	case PT_VM_ENTRY:
1398 		PROC_UNLOCK(p);
1399 		error = ptrace_vm_entry(td, p, addr);
1400 		PROC_LOCK(p);
1401 		break;
1402 
1403 	case PT_COREDUMP:
1404 		pc = addr;
1405 		CTR2(KTR_PTRACE, "PT_COREDUMP: pid %d, fd %d",
1406 		    p->p_pid, pc->pc_fd);
1407 
1408 		if ((pc->pc_flags & ~(PC_COMPRESS | PC_ALL)) != 0) {
1409 			error = EINVAL;
1410 			break;
1411 		}
1412 		PROC_UNLOCK(p);
1413 
1414 		tcq = malloc(sizeof(*tcq), M_TEMP, M_WAITOK | M_ZERO);
1415 		fp = NULL;
1416 		error = fget_write(td, pc->pc_fd, &cap_write_rights, &fp);
1417 		if (error != 0)
1418 			goto coredump_cleanup_nofp;
1419 		if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VREG) {
1420 			error = EPIPE;
1421 			goto coredump_cleanup;
1422 		}
1423 
1424 		PROC_LOCK(p);
1425 		error = proc_can_ptrace(td, p);
1426 		if (error != 0)
1427 			goto coredump_cleanup_locked;
1428 
1429 		td2 = ptrace_sel_coredump_thread(p);
1430 		if (td2 == NULL) {
1431 			error = EBUSY;
1432 			goto coredump_cleanup_locked;
1433 		}
1434 		KASSERT((td2->td_dbgflags & TDB_COREDUMPRQ) == 0,
1435 		    ("proc %d tid %d req coredump", p->p_pid, td2->td_tid));
1436 
1437 		tcq->tc_vp = fp->f_vnode;
1438 		tcq->tc_limit = pc->pc_limit == 0 ? OFF_MAX : pc->pc_limit;
1439 		tcq->tc_flags = SVC_PT_COREDUMP;
1440 		if ((pc->pc_flags & PC_COMPRESS) == 0)
1441 			tcq->tc_flags |= SVC_NOCOMPRESS;
1442 		if ((pc->pc_flags & PC_ALL) != 0)
1443 			tcq->tc_flags |= SVC_ALL;
1444 		td2->td_coredump = tcq;
1445 		td2->td_dbgflags |= TDB_COREDUMPRQ;
1446 		thread_run_flash(td2);
1447 		while ((td2->td_dbgflags & TDB_COREDUMPRQ) != 0)
1448 			msleep(p, &p->p_mtx, PPAUSE, "crdmp", 0);
1449 		error = tcq->tc_error;
1450 coredump_cleanup_locked:
1451 		PROC_UNLOCK(p);
1452 coredump_cleanup:
1453 		fdrop(fp, td);
1454 coredump_cleanup_nofp:
1455 		free(tcq, M_TEMP);
1456 		PROC_LOCK(p);
1457 		break;
1458 
1459 	default:
1460 #ifdef __HAVE_PTRACE_MACHDEP
1461 		if (req >= PT_FIRSTMACH) {
1462 			PROC_UNLOCK(p);
1463 			error = cpu_ptrace(td2, req, addr, data);
1464 			PROC_LOCK(p);
1465 		} else
1466 #endif
1467 			/* Unknown request. */
1468 			error = EINVAL;
1469 		break;
1470 	}
1471 out:
1472 	/* Drop our hold on this process now that the request has completed. */
1473 	_PRELE(p);
1474 fail:
1475 	if (p2_req_set) {
1476 		if ((p->p_flag2 & P2_PTRACEREQ) != 0)
1477 			wakeup(&p->p_flag2);
1478 		p->p_flag2 &= ~P2_PTRACEREQ;
1479 	}
1480 	PROC_UNLOCK(p);
1481 	if (proctree_locked)
1482 		sx_xunlock(&proctree_lock);
1483 	return (error);
1484 }
1485 #undef PROC_READ
1486 #undef PROC_WRITE
1487